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691.
A highly sensitive and selective potentiometric and voltammteric assay for the detection of Fe3+ using (E)‐3‐((2‐(2‐(2‐aminoethylamino) ethylamino) ethylimino)methyl)‐4H‐chromen‐4‐one (IFE(III)) ionophore was developed. To demonstrate the ion‐to‐electron transfer ability of MWCNT, these were incorporated in the ion‐selective membrane and response characteristics of Fe3+ electrode was compared with those of the traditional ion selective electrode. The electrode showed an improved Nernstian slope, lower detection limit, response time of less than 5 s and working in a pH range of 3.0 to 8.0. Differential pulse voltammetric studies were performed for IFE(III)‐Fe3+ complex in DMSO solvent medium at glassy carbon (GC) electrode. A linear relationship between the cathodic peak current and concentration of Fe3+ was observed in the range of 1.6×10?5 to 4.4×10?5 mol/L with a detection limit of 5.2×10?8 mol/L. The electrode shows remarkable selectivity for Fe3+ ions over alkali, alkaline earth, transition and heavy metal ions. The optimized electrode was successfully applied for the determination of Fe3+ ion in different real‐life samples using potentiometric technique. Theoretical calculations were used to support the complexation behavior of Fe3+ with IFE(III). 相似文献
692.
We report an efficient synthetic strategy to diverse hydantoins and thiohydantoins involving a three‐component reaction with the aid of deep eutectic solvent. Here, N,N′‐dimethyl urea and N,N′‐dimethyl thiourea play a dual role as reactant and reaction medium along with l ‐(+)‐tartaric acid. The three‐component reaction provides an easy access to 5‐amino‐1,3‐dialkyl‐substituted hydantoins and thiohydantoins in good yields. 相似文献
693.
Summary In the present investigations, the different oxidation states of vanadium have been estimated volumetrically in mixtures with the help of visual indicators.
Thanks of the authors are due to the C.S.I.R. authorities for providing a Research Fellowship to one of them (R.K.M.). 相似文献
Zusammenfassung Die verschiedenen Wertigkeitsstufen des Vanadiums wurden volumetrisch in Mischungen bestimmt. Zur Endpunktanzeige dienten visuelle Indicatoren.
Thanks of the authors are due to the C.S.I.R. authorities for providing a Research Fellowship to one of them (R.K.M.). 相似文献
694.
The problem of Robot Selection is of great relevance in the present times of automation. Traditionally such problems were addressed using conventional techniques of Multi Criteria Decision Making such as The Analytic Hierarchy Process (AHP) and The Multi Attribute Utility Theory (MAUT). This paper proposes a methodology for solving common Robot Selection problems using a modification of the conventional AHP by incorporating ‘Fuzzy Linguistic Variables’ in place of numbers. The methodology encapsulates creation of Fuzzy Interface for conversion of input and output variables into suitable linguistic variables. Further, employing the fuzzification process by assigning the linguistic variables to numerical values of the membership functions and formulating suitable decision rules, the procedure culminates into the defuzzification process for converting fuzzy output into crisp value and obtaining the result in the form of Fuzzy Score. The proposed model is explained using a numerical example. The paper also presents a validation of the proposed methodology over real world problems and provides directions for future research towards the end.Additional support was provided by the National Science Foundation. 相似文献
695.
This paper introduces the principle and design of an ultrasonic transducer system with auto-alignment mechanism. The proposed system is used for detecting foreign bodies (FBs) in beverage containers. Variation in reflection amplitude is analyzed as a function of the ultrasound beam incident angle to beverage container surface. It is concluded that there exists a quadratic relationship between the strength of the reflected signal and the incident angle. Furthermore, a calculation for effective angular increment for searching the normal of a curved surface is introduced. Experiments conducted using the prototype demonstrated that FBs are detectable in various juices. Experiments also observed some false echo signals that occur due to curved container surface. Threshold in confined time region is therefore set to ensure no fail of detection in low signal to noise ratio. This design is also applicable to non-destructive inspection for metal canned food. 相似文献
696.
The transient absorption spectrum (max = 320, 400 and 550 nm) obtained on reaction of OH radicals with 4-(methylthio)benzoic acid is assigned to a solute radical cation with a positive charge on the benzene ring. The reaction with specific one-electron oxidants also produced similar spectrum and the oxidation potential for the formation of solute radical cation is estimated to be between 1.4 and 1.6 V vs NHE. The reaction of eaq
- with the solute showed the formation of a transient absorption band at 320 nm and is assigned to solute radical anion with reduction potential more negative than-1.5 V. 相似文献
697.
Mittal K.C. Rohatgi V.K. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1988,16(6):601-605
A technique for controlling the voltage and current pulse duration of a gigawatt relativistic electron beam (REB) was investigated. The pulse duration of a beam of 250 keV and 10 kA was controlled from 60 ns to 10 ns by injecting gases (air,, argon, and hydrogen) into the diode gap at a pressure ranging from 10-5 torr to 10-1. The observed dependence of the pulse duration on the nature and pressure of the gas is explained in terms of volume ionization of the gas by beam electrons. It is concluded that the pulse duration is governed by the time at which the plasma density created by the beam reaches a critical value of the order of beam electron number density 相似文献
698.
Reaction of hydrated electrons with safranine T (SF+), a phenazine dye useful as sensitizer in photogalvanic cell and the transient semireduced species formed by this reaction
have been studied in SDS micellar medium using the technique of pulse radiolysis. Thee
aq
−
reaction with SF+ in the micellar environment was only marginally slower (5.1 × 109 dm3 mol−1 s−1) as compared to that in homogeneous aqueous medium (2.2 × 1010 dm3 mol−1 s−1) explicable on the basis of our finding that although a large fraction of the dye gets localized near the micelle Stern layer
where the molecule experiences a dielectric.constant of ≈40, a small but significant concentration of the dye exists in the
aqueous bulk as charge pair complex with the anionic surfactant monomer (association constant for the formation of the complex
being 2.8 × 104 dm3 mol−1). The transient semireduced absorption band observed in the micellar medium showed a red shift of ≈ 50 nm and also the decay
of the transient, which was very fast with 2k = 1 × 109 dm3 mol−1 s−1 in aqueous medium, was stable in the SDS micellar medium over a few tens of milliseconds suggesting that the radical is incorporated
deeper than the parent molecule in the SDS micelle. The effect of this stability on the photogalvanic conversion needs to
be examined. 相似文献
699.
V. Parthasarathy S.K. Sarkar V.P. Singhal A. Pandey K.V.S. Rama Rao Jai P. Mittal 《Chemical physics letters》1982,86(3):259-264
Vibrational excitation of CDF3 and NH3 at 970 cm?1 by a TEA CO2 laser results in deuterium—hydrogen exchange suppressing the IR-laser-induced multiphoton chemistry of CDF3. 相似文献
700.
Propagation of circularly polarized waves along a spatially uniform but temporally fluctuating magnetic field is considered. It is shown that the coherent waves are damped. The results are compared with those for Krook's relaxation model. 相似文献